Re: X-10 RF meter (was Re: XTB II Review)

[nobody@xxxxxxxxxxxx (Dave Houston)]

"Jeff Volp" <JeffVolp@xxxxxxx> wrote:

>> There are a few hundred BX24-AHT users who will tell you otherwise.
>
>I know the BX24-AHT gave a relative signal level indication, but I don't
>recall anything saying what that readout meant in dBm.
>
>Here is a cheap receiver with a true RSSI output:
>
>http://www.okwelectronics.com/datasheets/DS.0015-1.pdf
>
>Is it possible to get that kind of RSSI data from the received signal analog
>output?

Since Bobby G. thought the prices for RF field strength meters were too
high, I thought the goal was an inexpensive device that could be used to
track down mystery X-10 RF signals. That's what I proposed.

The module you suggest costs quite a bit more than the one I suggested  -
more than the $15 I suggested as the total cost (and my guesstimate was a
bit high). I couldn't get the OKW price quote to work but, from past
experience, they mark these up over the RF Solutions price.


http://www.rfsolutions.co.uk/acatalog/AM_Superhetrodyne_Receiver_Modules.html

How do you propose to get a dBm reading from that module? Why do you need a
dBm reading to vary the intensity of an LED?

How do you propose to tune that module to 310MHz? It is not tunable.

I have one of those superhets somewhere but I really don't want to take the
time to do a side-by-side comparison for this application.

The method I've used correlates quite well with distance between the
transmitter and receiver - from a few feet to more than a hundred feet.

Since my method actually measures the depth of modulation (of the recovered
baseband) it might be a better indicator than the RSSI output from the
superhet receiver but it's hard to say without knowing exactly how they
develop their RSSI voltage.

It's possible to increase the overall signal amplitude (at the linear output
pin) by merely using a higher supply voltage for the receiver but the depth
of modulation does not change nor is there an increase in effective range.

http://davehouston.net
http://tech.groups.yahoo.com/group/roZetta/
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